1. Field of the Invention
The present invention relates to a composition which includes both one or more cationic polymers and anionic xanthan gum. More specifically, the composition includes polygalactomannans which are cationically charged in combination with anionic substituted xanthan gum. The resulting compositions exhibit enhanced viscosities as compared to the viscosities obtained when using the polygalactomannans and xanthan gum separately or as compared to the viscosity of using polygalactomannans in combination with nonionic xanthan gum.
2. Technology Description
Natural and synthetic gums have been used as thickeners for foods, coatings, paints, explosive slurries, oil well fluids, cosmetics, and many other functional applications. One natural gum that has been widely used as a suspending and viscosity agent is xanthan gum. Aqueous sols of xanthan gum are plastic in nature and exhibit higher gel strengths than sols of most other gums. Blends of xanthan gum with other gums are known and each blend exhibits properties unique unto itself. One set of gums which has been suggested for blending with xanthan gum are the galactomannans.
For example, Schuppner et al in U.S. Pat. Nos. 3,507,664; 3,519,434; 3,557,016; and 3,659,026 discuss a number of uses for compositions which include both xanthan gum and locust bean gum. Amongst the uses mentioned are: milk gels (U.S. Pat. No. 3,507,664), meat gels (U.S. Pat. No. 3,519,434), heat reversible gels in general (U.S. Pat. No. 3,557,016) and agricultural uses (U.S. Pat. No. 3,659,026). A basic concept of each of these patents is that the combination of xanthan gum with locust bean gum for each of the functional applications yields a composition which, when displaced in a solvent, demonstrates excellent gelling attributes.
U.S. Pat. No. 4,038,206 suggests that higher viscosities can be obtained when the locust bean gum used in combination with xanthan gum is a hydroxyalkyl locust bean gum. The hydroxyalkyl locust bean gums include the water soluble hydroxypropyl ethers of locust bean gum, hydroxyethyl ethers of locust bean gum and hydroxybutyl ethers of locust bean gum. The hydroxyalkyl locust bean gum is prepared by reacting an alkylene oxide with locust bean gum to form one or more ether linkages. The suggested molar amount of alkylene oxide per mole of locust bean gum is 0.05 to 0.5.
U.S. Pat. No. 4,162,925 suggests that phosphated esters of locust bean gum having a degree of substitution ranging from about 0.03 to about 0.5 be used in combination with xanthan gum to form viscous liquids and/or firm gels. These materials are particularly suggested for use as suspending agents for oil well drilling and for use in precision planting procedures referred to as fluid drilling. The examples of the patent suggest that the phosphated esters utilized are anionic in nature.
The combination of xanthan gum with other galactomannans, such as guar gum and those derived from guar gum are also discussed in the literature. For example, U.S. Pat. No. 3,748,201 suggests thickening compositions containing xanthan gum and hydroxyalkyl ethers of guar gum. The hydroxyalkyl ether of guar gum is prepared by reacting guar gum with an alkylene oxide in the presence of an alkaline catalyst. The preferred degree of substitution of the guar gum resulting from the formation of ether linkages is preferably between about 0.2 to about 1.2. The compositions are suggested for use in dyeing yarns for carpeting and for explosives.
It is hypothesized that the interaction between xanthan gum and the above described polygalactomannans is of a molecular nature. Polygalactomannans with less galactose side-chains and/or less uniform distribution of galactose units will interact with xanthan gum more strongly than the polygalactomannans with higher galactose content and/or more uniform distribution of galactose over the mannan main chain.
U.S. Pat. No. 3,467,647 disclose polysaccharides containing both cationic and anionic substituents. Amongst the starting polysaccharides which are then modified according to this patent include starches, locust bean gum (carob gum) and guar gum. Cationic substituents include primary, secondary, or tertiary amino groups or quaternary ammonium, sulfonium or phosphinium groups. Suggested anionic substituents include carboxyl, sulfonate, sulfate or phosphate groups. Example 9 of this patent discloses guar gum as the polysaccharide, trimethylammoniumhydroxypropyl as the cationic groups, and phosphates as the anionic groups. The degree of substitution for each of these groups in this example is 0.05.
Chem. Abstracts CA115(16):16250p discusses the uses of certain polymer combinations which provide enhanced viscosities as compared to the viscosities of the individual polymers. Combinations mentioned include poly(styrene sulfonate) and either xanthan gum or hydroxyethyl cellulose, poly(vinyl sulfonate) and xanthan gum, a quaternary-ammonium-salt modified guar and either hydroxypropyl guar or hydroxyethyl cellulose, and a sulfonated guar and either hydroxyethyl cellulose or carboxymethylhydroxyethyl cellulose. These combinations are suggested for use in oil recovery.
Similarly, DD 281966 discloses a gel former which has both cationic and anionic polymers and provides a synergistic increase in viscosity as compared to solutions which contain separate amounts of the polymers. The anionic polymer is preferably a poly(dimethyl-diallylammonium chloride) containing pyrrolidinium units and the cationic polymer is preferably carboxymethylcellulose with a degree of substitution of 0.6-1.2.
U.S. Pat. Nos. 4,264,322; 4,403,360 and 4,454,617 disclose dye compositions for textile fibers. The compositions comprise an admixture of immiscible gel phases, wherein one gel phase is thickened with a cationic gelling agent and wherein a second gel phase, which is dispersed in the first gel phase, is thickened with an anionic gelling agent. Suggested cationic gelling agents for the first phase include cationic polygalactomannans containing quaternary ammonium ether substituents. Suggested anionic gelling agents for the second phase include hydrocolloids which have the same type of basic polymeric structure as the cationic gelling agents, except that in place of the cationic group there is substituted an anionic group such as a carboxylic acid, sulfonic acid, or sulfate.
DE 1,518,731 discloses that galactomannans or glucomannans may be etherified with .beta.-halogen ethane sulfonic acid or halogen methane sulfonic acids in the presence of base to yield compositions which can function as textile finishes, sizes and print thickeners.
U.S. Pat. No. 3,912,713 and FR 2,242,401 disclose guar gum derivatives and processes for preparing the derivatives. The derivatives are prepared by adding a substituent to guar gum splits in the presence of water, and typically, base. Amongst the substituents (derivatizing agents) suggested for use in these patents are haloalkylsulfonic acids, such as bromoethanesulfonic acid and chlorohydroxypropanesulfonic acid, epoxyalkyl sulfonic acids, such as epoxypropane sulfonic acid, and .alpha., .beta.-alkylene sulfonic acids, such as ethylene sulfonic acid. These compounds are suggested for use as thickening agents, stressing, sizing and finishing agents, protective colloids and as agents for stabilizing dispersions and emulsions.
U.S. Pat. No. 4,031,305 discloses sulfohydroxypropyl ethers of polygalactomannans having a degree of substitution between about 0.01 and 3. The ethers are prepared by contacting solid guar gum or locust bean gum with a 3-halo-2-hydroxypropanesulfonic acid or acid salt in the presence of base. The galactomannan ethers are alleged to be anionic in nature and are proposed for use in petroleum, textile, printing, paper, food and pharmaceutical industries.
U.S. Pat. No. 4,057,509 discloses the formation of an acidic gel by contacting a polygalactomannan with an allyl halide, followed by exposing the formed polygalactomannan allyl ether material to a stream of sulfur dioxide. The gels are suggested for use in oil well drilling mud compositions and oil well fracturing compositions.
Despite the above, there still is a need for compositions which demonstrate enhanced viscosity behavior and which rely on forces in addition to molecular ones.